Trichloroethylene (TCE), one of the most common groundwater pollutants, is a known hepatotoxin and carcinogen. It has been widely used by industry and the military as a degreaser for metal parts: according to the Agency for Toxic Substances and Disease Registry, more than eight hundred Superfund sites in the United States are contaminated with TCE. Poplar, which can take up and degrade TCE, is an attractive plant for phytoremediation of TCE and other organic contaminants due to its high growth rate, extensive root system, high rates of water uptake from the soil, and ease of genetic manipulation. While transgenic poplar for improved TCE degradation has been successfully field tested, there are significant regulatory and breeding hurdles preventing the large-scale use of this technology. Recently researchers have determined the potential of endophytes, symbiotic bacteria and fungi that live within plant cells, to break down organic contaminants and improve the phytoremediation capability of non-transgenic plants. Unlike other microbes that have been used for phytoremediation, endophytes live within the plant and therefore are expected to persist better at the site, continuing to degrade TCE as long as their plant partner survives. The laboratory of Dr. Sharon Doty is one of the pioneers in studying endophytes to improve plant growth and health, having worked in this field for over a decade. Recently her laboratory has isolated endophytes from poplar growing in sites contaminated with TCE and other organic pollutants. Some of these microbes exhibit high rates of TCE degradation when grown in the lab. Her laboratory is currently developing methods to inoculate these TCE-degrading endophytes into poplar and will work with Edenspace on this SBIR project to demonstrate that the new poplar/endophyte systems have significantly better TCE phytoremediation performance than control poplar. Edenspace will also develop molecular markers to identify the specific endophytes, in order to confirm in a field test that the microbes can persist in the poplar for months. Upon successful completion of this SBIR project Edenspace will partner with Geosyntec, a leading environmental engineering firm, to introduce this novel technology to the remediation industry. PUBLIC HEALTH RELEVANCE: Trichloroethylene (TCE) is a known carcinogen and significant environmental contaminant as a result of to extensive use by the military and industry. Poplar trees have been used as a natural method to remove TCE from contaminated groundwater. In this project scientists from Edenspace and the University of Washington will utilize recently identified microbes that can act with the poplar to greatly increase TCE removal rates. Development of this improved remediation system will reduce exposure of humans and wildlife to TCE.